An example of the prior-art solutions is described in document U.S. 2014/0338243. According to the solution, breech is arrested in a rear position in a catch being provided in a side of the breech. During both-sided releasing, the control, which is positioned at the opposite side of the catch, is subject to distortion.
Document WO/US2016/040217 describes solution which does not allow for a both-sided releasing of the breech.
In another design, the breech is caught by the feeding bridge, but only unilaterally.
Thus, in the prior-art designs, during the releasing the parts are exposed to asymmetrical forces and consequently to asymmetrical frictional resistances and distortion, which leads to a higher risk of failures and impaired control of the pistol.